1. Technical Field
Embodiments of the invention relate generally to electric power converters. Other embodiments relate to communication protocols for electric power converters.
2. Discussion of Art
Trains typically feature a number of cars that are pushed or pulled by a locomotive. The locomotive has traction wheels engaged with the track. In modern designs, electric wheel motors drive the traction wheels. The electric wheel motors are powered via electrical distribution from one or more engine-driven generators housed within the locomotive. The traction wheels and wheel motors can be reversibly configured, to also act as brakes for slowing the locomotive.
Similarly, in the mining industry, large off-highway vehicles (“OHVs”) usually employ electrically motorized wheels for propelling or retarding the vehicle. In particular, OHVs typically include a large horsepower diesel engine in conjunction with an alternator, a main traction inverter, and a pair of wheel drive assemblies housed within the rear tires of the vehicle. The diesel engine is directly associated with the alternator such that the diesel engine drives the alternator. The alternator powers the main traction inverter, in which semiconductor power switches commutate the alternator output current to provide electrical power to electric drive motors of the two wheel drive assemblies.
In both locomotive and OHV applications, solid state power converters (e.g., the aforementioned traction inverter) are used to provide high voltage current from the generators or alternators to the wheel motors. Such power converters include inductive coils to step down the voltage as well as semiconductor power switches to commutate the current. Although the above-described applications are typical, it will be appreciated that power converters can be used in many other settings.
Generally, operation of a power converter is accomplished by applying alternately two different gate voltage levels (e.g., an “off” voltage and an “on”/drive voltage) to individual semiconductor power switches via corresponding gate drive units. It is a known problem that semiconductor power switches respond differently to gate voltages, depending on electrical parameters of the circuit in which the power switches are connected. Thus, power converter efficiency varies across the operating ranges of electrical parameters that impact semiconductor power switch response.
Therefore, it is desirable to monitor electrical parameters during operation of a power converter and adapt to such parameters to increase converter efficiency.